#2: yes, check for a half case like the Gariz (you can find lots of threads here if you search)
#3: you use a lens hood when you want to reduce flare, when using the lens outside during a sunny day etc...
edit: Jim just beat me to it by seconds, lol :P
SEL 18-55mm /3.5-5.6 SEL 16mm /2.8
MD 50mm /1.7 MD 35-70mm /3.5 w/Macro MD Tele-Rokkor 135mm /3.5 MD 35-105mm /3.5-4.5 MD 28-85mm /3.5-4.5 MD 35-135mm /3.5-4.5 MD Rokkor X 50-135mm /3.5
...and always looking for more MDs :P